1. The Field of the Invention
This invention is concerned with an applicator nozzle for applying a band of liquid composition, especially a viscous liquid adhesive composition e.g. hot melt adhesive composition to a surface.
2. Description of the Prior Art
In the field of adhesive bonding it is known to apply adhesive composition in fluid condition to a workpiece. It is well known for example to apply hot melt adhesives by means of static applicators or hand-held applicators. Hot melt adhesives used in production of many types of articles are of a kind which achieve their adhesive properties by mere setting of the composition on cooling. However, it has been proposed to employ in certain trades adhesive compositions which achieve at least some of their adhesive properties by virtue of a curing reaction, which may be effected for example by atmospheric moisture. With such compositions it is desirable to provide means for dispensing and applying the composition, which means is capable of continued production operation despite clogging of the applicator nozzle which may result from curing of the composition in the mechanism. It is thus convenient to provide an arrangement whereby the applicator nozzle may be readily cleaned.
It has been proposed to employ applicator nozzles of silicone rubber composition for applying heated compositions to workpieces and which are provided with a resiliently flexible applicator portion. One nozzle which has been proposed for use in applying viscous, liquid, hot melt adhesive compositions is described in our U.S. Pat. No. 4,419,393 and comprises a tapering applicator portion which is resiliently flexible and is provided with an adhesive guiding surface which extends to a narrow terminal spreading surface of the applicator portion, the adhesive-guiding surface being concave about an axis which extends transversely of the spreading surface, and an elongated orifice opening through the adhesive-guiding surface and extending generally parallel to the spreading surface. Such an applicator nozzle has been found suitable for use in static applicators but is not well adapted for use in hand-held applicators, at least for certain applications. For example, it is sometimes necessary to apply a band of adhesive to a workpiece surface on a curved path, e.g. in cementing edge portions of shoe soles, and this is difficult, using a nozzle as referred to above in a hand-held applicator because of manipulation difficulties in ensuring that the nozzle has appropriate orientation relative to direction of travel along the path.